Better bot coverage for (Vk, Mtl) x MSAA

- Stop testing Metal-MSAA on our Gen8 Mac. These GPUs are slow and buggy
  with MSAA (we already have them disabled on other backends).
- Add Metal bots with the HD615 to get testing on a Gen9 GPU. This
  should have better performance and more correct results. Also move the
  DDL tests to those machines, to get testing on a newer/faster machine.
- Add MSAA configs to Vulkan and Metal perf bots (except for old Intel).

Bug: skia:9023 skia:8243
Change-Id: I214c6c4ef7b6e1401719e62e29fd5d2ad05b6aa1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/229379
Reviewed-by: Greg Daniel <egdaniel@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
8 files changed